Part of set of 27 glass negatives and one celluloid negative depicting airplanes and aviators of Panama-Pacific International Exposition, San Francisco; Lockheed (Lougheed) Model G in flight over San Francisco Bay; military ships and Alcatraz Island in background; number “21729” written on image; photograph taken in 1915; handwritten inscription on original sleeve, “21729 / H. J. Stinson in hydroplane.”